The present investigation will assess the strength of prediction of two views of drug use onset, as applied to smokeless tobacco and cigarette smoking. Specifically, a five-year school-based investigation (taking place in both rural and urban settings) consisting of four phases is proposed. The first phase will consist of a series of small-scale assessment studies. Three types of assessment, guided in method by two contrasting views of group conformity ("normative", and "informational"), will try to discern the antecedents, parameters, immediate consequences, and maintenance of smokeless tobacco and cigarette use in seventh and tenth grade cohorts. Results from each assessment will be used to generate or adapt prevention and cessation intervention approaches anchored to specific findings. Phase 2 will tie the small-scale assessment information together into a large-scale, longitudinal self-report assessment study, which will provide a one-year pretreatment evaluation of prevention and cessation intervention subjects as well as a large-scale assessment of the relevance of the two views of conformity to the development and maintenance of smokeless tobacco and cigarette use. In Phase 3a, prevention curricula development and piloting will be done (for a one-year period) based on the results of the assessment studies. In Phase 3b, cessation program development and piloting will be done, and will continue for a two-year period, because both recruitment strategies and cessation intervention strategies will need to be developed and piloted. In Phase 4a, a large-scale prevention intervention study will begin, followed by a two-year followup period, and in Phase 4b, a large-scale cessation intervention will begin during the fourth year, followed by a one- year followup period. The main objective, given assessment phase results, is to systematically develop and evaluate broad-based educational interventions for preventing and reducing the use of smokeless tobacco and cigarettes among teenagers, (a) comparing a "social resistance" versus a "social identify/values" approach for the prevention intervention and (b) comparing these two prevention-derived approaches to two adult cessation-derived approaches for the cessation intervention.